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About Patmos

Patmos is a time-predictable VLIW processor. Patmos is the processor for the T-CREST project. See also: and

The Patmos Reference Handbook contains build instructions in Section 5.

For questions and discussions join the Patmos mailing list at:

Getting Started

Several packages need to be installed. The following apt-get lists the packages that need to be installed on a Ubuntu Linux:

sudo apt-get install git default-jdk gitk cmake make g++ texinfo flex bison \
  subversion libelf-dev graphviz libboost-dev libboost-program-options-dev ruby-full \
  liblpsolve55-dev python zlib1g-dev gtkwave gtkterm scala

On a restricted machine (e.g. Cloud9) the bare minimum is:

sudo apt-get install default-jdk git cmake make g++ texinfo flex bison \
  subversion libelf-dev graphviz libboost-dev libboost-program-options-dev ruby-full \
  python zlib1g-dev

Install sbt with:

echo "deb /" | sudo tee -a /etc/apt/sources.list.d/sbt.list
sudo apt-key adv --keyserver hkp:// \
  --recv 2EE0EA64E40A89B84B2DF73499E82A75642AC823
sudo apt-get update
sudo apt-get install sbt

We assume that the T-CREST project will live in $HOME/t-crest. Before building the compiler, add the path to the compiler executables into your .bashrc or .profile:

export PATH=$PATH:$HOME/t-crest/local/bin

Use an absolute path as LLVM cannot handle a path relative to the home directory (~).

Patmos and the compiler can be checked out from GitHub and are built as follows:

mkdir ~/t-crest
cd ~/t-crest
git clone misc

For developers with push permission the ssh based clone string is:

git clone misc will checkout several other repositories (the compiler, library, and the Patmos source) and build the compiler and the Patmos simulator. Therefore, take a cup of coffee and find some nice reading (e.g., the Patmos Reference Handbook).

We can start with the standard, harmless looking Hello World:

main() {
    printf("Hello Patmos!\n");

With the compiler installed it can be compiled to a Patmos executable and run with the simulator as follows:

patmos-clang hello.c
pasim a.out

However, this innocent examples is quiet challenging for an embedded system. For further details and how to build Patmos for an FPGA see Section 6 in the Patmos Reference Handbook.

You can also build the Patmos handbook yourself from the source. You first need to install LaTeX (about 3 GB) with:

sudo apt-get install texlive-full doxygen

The handbook is then built with:

cd patmos/doc

Known Issues

  • patmos-llvm currently does not compile with clang > 3.4 on Ubuntu 15.04. As a workaround, uninstall clang, install clang-3.4 and create symlinks clang and clang++ to clang-3.4 and clang++-3.4.